1. Field of the Invention
The present invention relates to a rotor turning device for a wind turbine generator and a rotor turning method. In particular, the invention relates to a rotor turning device for rotating a rotation axis of a wind turbine generator that increases rotational speed of a rotor head with a gear box to transmit into a generator, and to a method for turning the rotor.
2. Description of the Related Art
In recent years, from a view point of preserving the global environment, the use of wind turbine generators to generate reusable energy has become popular.
In general, a wind turbine generator comprises a rotor head equipped with blades, a nacelle accommodating a drive train and a generator, and a tower supporting the nacelle. The drive train is for transmitting a torque from the rotor head side to the generator side, and usually includes a gear box so that rotational speed of the rotor head is increased to transmit to the generator.
When performing maintenance work on the wind turbine generator, it often becomes necessary to rotate the rotation axis (or the rotor head connected to the rotation axis).
For example, to lubricate a main shaft bearing of the wind turbine generator, the rotation axis must be slowly rotated in order to evenly apply grease to the entire shaft bearing. Also, to assemble and disassemble the blades, the rotor head must be rotated so that the blades come into a horizontal position. In addition, for safety measures during maintenance work, the rotation axis should be secured with lock pins to prevent it from rotating. Again in this case, the rotation axis needs to be rotated to a position where the lock pins can be inserted.
Some convenient methods for rotating the rotation axis of the wind turbine generator for these purposes are to hand grasp and turn the brake disk attached to the rotation axis at the later stage of the gear box, or to turn the rotation axis by utilizing wind power applied to the blades.
However, with these methods, it was difficult to highly accurately rotate the rotation axis into a predetermined position. Further, a method with higher safety was desired.
Therefore, a so-called rotor turning device that forcibly rotates the rotation axis of the wind turbine generator has been proposed.
For example, US Patent Application Publication No. 2009/0278359 describes a rotor turning device that forcibly drives a speed-up gear housed in a gearbox (a gear box) from outside the gearbox. This rotor turning device comprises a drive pinion that meshes with the speed-up gear inside the gearbox and a screwdriver that is attached to the outside of the gearbox to transmit a torque to the drive pinion. With this structure, the torque from the screwdriver is transferred to the speed-up gear via the drive pinion making the rotation axis rotate with the speed-up gear.
Related Patent Documents
    [Pre-Grant Publication Document 1] US2009/0278359